Ulrich Engler, nicknamed "Richie," has been on the run since 2007, when a warrant was issued for his arrest and he disappeared in the US, the Bild newspaper reported on Monday.
Engler, who never worked in a bank, is thought to have spent several years pretending to be an investment expert who had developed a computer programme allowing him to recognize stock markets developments before anyone else. Around 3,500 people are thought to have handed him their savings in Germany alone.
He used the money to live a life of luxury and pay off other investors.
American authorities found the 52-year-old after his fingerprints were taken when he was stopped on a drink-driving charge in 2011.
He was arrested in July in Las Vegas, where the FBI confiscated more than a thousand valuable works of art from his home, including an original painting by Russian abstract artist Wassily Kandinsky.
Engler was extradited to Germany on Friday, and is expected to be moved to a prison in Mannheim on Monday.
"I know that I have reached rock bottom," Engler said in a statement through his lawyer Steffen Lindberg. "But I'm glad that I'm not on the run any more, and that I'm back on German soil."
Lindberg told the paper, "My client is ready to take responsibility and wants to cooperate with authorities."
If convicted of the embezzlement charges, he could face up to 15 years in prison.